Hair care composition

ABSTRACT

A method for relaxing hair comprising the following steps:
         i) applying to the hair for a sufficient period of time to lanthionize the hair a relaxer composition;   ii) terminating the lanthionization process;   iii) applying to the lanthionized hair a post-lanthionization composition comprising a monoglyceride having a C16 to C22 alkyl ester group.

The present invention is directed to a hair relaxing composition and amethod of relaxing hair.

Hair relaxers are compositions used to relax or straighten curly orkinky hair. Most hair relaxers straighten hair by disrupting disulfidebonds of the hair fibres with an alkaline agent or reducing agent. Thechemical disruption of disulfide bonds is usually combined withmechanical straightening of the hair (eg by combing). The straighteningprocess is generally terminated by rinsing and/or the application of aneutralizing composition.

A source of hydroxide ions is usually the preferred alkaline agent usedto straighten hair. The term “lanthionizing” is used when referring tohair relaxed or straightened by hydroxide ions, as the straighteningreaction sequence with hydroxide ions results in lanthionine residueformation.

Most frequently, commercial relaxing compositions are in the form ofgels or emulsions and contain varying proportions of strongwater-soluble bases, such as sodium hydroxide (NaOH). Also used areslightly-soluble metal hydroxides, such as calcium hydroxide (Ca(OH)₂),which can be converted in situ to soluble bases, such as guanidinehydroxide.

Hair relaxers leave the hair treated therewith feeling rough,unconditioned and brittle. The present invention relates to hairrelaxing systems which leave the hair less prone to breakage and feelingsmooth.

In one aspect the present invention relates to a method for relaxinghair comprising the following steps:

-   -   i) applying to the hair for a sufficient period of time to        lanthionize the hair a relaxer composition;    -   ii) terminating the lanthionization process;    -   iii) applying to the lanthionized hair a post-lanthionization        composition comprising a mono glyceride having an C16 to C22        alkyl ester group.

A further aspect of the invention is the use of a mono glyceride havingan C16 to C22 alkyl ester group a post-treatment composition fordecreasing hair breakage.

As disclosed above the present invention relates to post-treatmentcomposition for application after application of a relaxing composition.In the context of the present invention “relaxing composition” means acomposition comprising at least one hydroxide ion generator in an amountsufficient to effect lanthionization of keratin fibres. The termpost-treatment refers to a treatment applied to the hair after thelathionization process, and preferably after any subsequent terminationprocess.

The hydroxide ion generator may be chosen from those compositions thatproduce hydroxide ions appropriate for the lanthionization of hair. Asused herein, “hydroxide ion generator” refers to both compounds andcompositions that generate hydroxide ions, and compounds andcompositions that comprise hydroxide ions. Hydroxide ion generators may,for example, be chosen from traditional “lye” and “no lye” hair relaxercompositions and other soluble or slightly soluble hydroxide ionsources. Preferably, the hydroxide ion is generated in situ. Preferredhydroxide ion generators are strong water-soluble bases, particularlypreferred is sodium hydroxide.

The post lanthionization composition comprises a monoglyceride having anC16 to C22 alkyl ester group.

Preferably the mono glyceride comprises a long chain unsaturated group,and is more preferably glyceryl monololeate.

The level of monoglyceride within the post-treatment composition ispreferably from 1 to 10 wt %, more preferably from 3.5 to 7.5 wt % ofthe total composition.

The post treatment composition will preferably comprise one or moreconditioning surfactants which are cosmetically acceptable and suitablefor topical application to the hair.

Suitable conditioning surfactants are selected from cationicsurfactants, used singly or in admixture.

Cationic surfactants useful in compositions of the invention containamino or quaternary ammonium hydrophilic moieties which are positivelycharged when dissolved in the aqueous composition of the presentinvention.

Examples of suitable cationic surfactants are those corresponding to thegeneral formula:

[N(R₁)(R₂)(R₃)(R₄)]⁺(X)⁻

in which R₁, R₂, R₃, and R₄ are independently selected from (a) analiphatic group of from 1 to 22 carbon atoms, or (b) an aromatic,alkoxy, polyoxyalkylene, alkylamido, hydroxyalkyl, aryl or alkylarylgroup having up to 22 carbon atoms; and X is a salt-forming anion suchas those selected from halogen, (e.g. chloride, bromide), acetate,citrate, lactate, glycolate, phosphate nitrate, sulphate, andalkylsulphate radicals.

The aliphatic groups can contain, in addition to carbon and hydrogenatoms, ether linkages, and other groups such as amino groups. The longerchain aliphatic groups, e.g., those of about 12 carbons, or higher, canbe saturated or unsaturated.

The most preferred cationic surfactants for conditioner compositions ofthe present invention are monoalkyl quaternary ammonium compounds inwhich the alkyl chain length is C8 to C14.

Suitable examples of such materials correspond to the general formula:

[N(R₅)(R₆)(R₇)(R₈)]⁺(X)⁻

in which R₅ is a hydrocarbyl chain having 8 to 14 carbon atoms or afunctionalised hydrocarbyl chain with 8 to 14 carbon atoms andcontaining ether, ester, amido or amino moieties present as substituentsor as linkages in the radical chain, and R₆, R₇ and R₈ are independentlyselected from (a) hydrocarbyl chains of from 1 to about 4 carbon atoms,or (b) functionalised hydrocarbyl chains having from 1 to about 4 carbonatoms and containing one or more aromatic, ether, ester, amido or aminomoieties present as substituents or as linkages in the radical chain,and X is a salt-forming anion such as those selected from halogen, (e.g.chloride, bromide), acetate, citrate, lactate, glycolate, phosphatenitrate, sulphate, and alkylsulphate radicals.

The functionalised hydrocarbyl chains (b) may suitably contain one ormore hydrophilic moieties selected from alkoxy (preferably C₁-C₃alkoxy), polyoxyalkylene (preferably C₁-C₃ polyoxyalkylene), alkylamido,hydroxyalkyl, alkylester, and combinations thereof.

Preferably the hydrocarbyl chains R₁ have 12 to 14 carbon atoms, mostpreferably 12 carbon atoms. They may be derived from source oils whichcontain substantial amounts of fatty acids having the desiredhydrocarbyl chain length. For example, the fatty acids from palm kerneloil or coconut oil can be used as a source of C8 to C12 hydrocarbylchains.

Typical monoalkyl quaternary ammonium compounds of the above generalformula for use in shampoo compositions of the invention include:

-   (i) lauryl trimethylammonium chloride (available commercially as    Arquad C35 ex-Akzo); cocodimethyl benzyl ammonium chloride    (available commercially as Arquad DMCB-80 ex-Akzo)-   (ii) compounds of the general formula:

[N(R₁)(R₂)((CH₂CH₂O)_(x)H)((CH₂CH₂O)_(y)H)]⁺(X)⁻

in which:x+y is an integer from 2 to 20;R₁ is a hydrocarbyl chain having 8 to 14, preferably 12 to 14, mostpreferably 12 carbon atoms or a functionalised hydrocarbyl chain with 8to 14, preferably 12 to 14, most preferably 12 carbon atoms andcontaining ether, ester, amido or amino moieties present as substituentsor as linkages in the radical chain;R₂ is a C₁-C₃ alkyl group or benzyl group, preferably methyl, andX is a salt-forming anion such as those selected from halogen, (e.g.chloride, bromide), acetate, citrate, lactate, glycolate, phosphatenitrate, sulphate, methosulphate and alkylsulphate radicals.

Suitable examples are PEG-n lauryl ammonium chlorides (where n is thePEG chain length), such as PEG-2 cocomonium chloride (availablecommercially as Ethoquad C12 ex-Akzo Nobel); PEG-2 cocobenzyl ammoniumchloride (available commercially as Ethoquad CB/12 ex-Akzo Nobel); PEG-5cocomonium methosulphate (available commercially as Rewoquat CPEMex-Rewo); PEG-15 cocomonium chloride (available commercially as EthoquadC/25 ex-Akzo).

-   (iii) compounds of the general formula:

[N(R₁)(R₂)(R₃)((CH₂)_(n)OH)]⁺(X)⁻

in which:n is an integer from 1 to 4, preferably 2;R₁ is a hydrocarbyl chain having 8 to 14, preferably 12 to 14, mostpreferably 12 carbon atoms;R₂ and R₃ are independently selected from C₁-C₃ alkyl groups, and arepreferably methyl, andX is a salt-forming anion such as those selected from halogen, (e.g.chloride, bromide), acetate, citrate, lactate, glycolate, phosphatenitrate, sulphate, and alkylsulphate radicals.

Suitable examples are lauryldimethylhydroxyethylammonium chloride(available commercially as Prapagen HY ex-Clariant).

Mixtures of any of the foregoing cationic surfactants compounds may alsobe suitable.

Examples of suitable cationic surfactants include:

quaternary ammonium chlorides, e.g. alkyltrimethylammonium chlorideswherein the alkyl group has from about 8 to 22 carbon atoms, for exampleoctyltrimethylammonium chloride, dodecyltrimethylammonium chloride,hexadecyltrimethylammonium chloride, cetyltrimethylammonium chloride,octyldimethylbenzylammonium chloride, decyldimethylbenzylammoniumchloride, stearyldimethylbenzylammonium chloride,didodecyldimethylammonium chloride, dioctadecyldimethylammoniumchloride, tallow trimethylammonium chloride, cocotrimethylammoniumchloride, and the corresponding salts thereof, e.g., bromides,hydroxides. Cetylpyridinium chloride or salts thereof,e.g., chloride

Quaternium −5 Quaternium −31 Quaternium −18

and mixtures thereof.

In the conditioners of the invention, the level of cationic surfactantis preferably from 0.01 to 10, more preferably 0.05 to 7, mostpreferably 0.5 to 5 wt % of the total composition.

The weight ratio of cationic conditioning agent to monoglyceride withinthe post-treatment composition is preferably from 1:10 to 10:1, morepreferably from 1:5 to 5:1.

Post treatment compositions of the invention preferably additionallycomprise a fatty alcohol material. The combined use of fatty alcoholmaterials and cationic surfactants in conditioning compositions isbelieved to be especially advantageous, because this leads to theformation of a lamellar phase, in which the cationic surfactant isdispersed.

By “fatty alcohol material” is meant a fatty alcohol, an alkoxylatedfatty alcohol, or a mixture thereof.

Representative fatty alcohols comprise from 8 to 22 carbon atoms, morepreferably 16 to 20. Examples of suitable fatty alcohols include cetylalcohol, stearyl alcohol and mixtures thereof. The use of thesematerials is also advantageous in that they contribute to the overallconditioning properties of compositions of the invention.

Alkoxylated, (e.g. ethoxylated or propoxylated) fatty alcohols havingfrom about 12 to about 18 carbon atoms in the alkyl chain can be used inplace of, or in addition to, the fatty alcohols themselves. Suitableexamples include ethylene glycol cetyl ether, polyoxyethylene (2)stearyl ether, polyoxyethylene (4) cetyl ether, and mixtures thereof.

The level of fatty alcohol material in conditioners of the invention issuitably from 0.01 to 15, preferably from 0.1 to 10, and more preferablyfrom 0.1 to 5 wt %. The weight ratio of cationic surfactant to fattyalcohol is suitably from 10:1 to 1:10, preferably from 4:1 to 1:8,optimally from 1:1 to 1:7, for example 1:3.

Post treatment compositions of the invention can also contain a cationicpolymer.

The compositions of the invention can contain, emulsified droplets of asilicone conditioning agent, for enhancing conditioning performance. Thesilicone is insoluble in the aqueous matrix of the composition and so ispresent in an emulsified form, with the silicone present as disperseddroplets.

Suitable silicones include polydiorganosiloxanes, in particularpolydimethylsiloxanes which have the CTFA designation dimethicone. Alsosuitable for use compositions of the invention (particularly shampoosand conditioners) are polydimethyl siloxanes having hydroxyl end groups,which have the CTFA designation dimethiconol. Also suitable for use incompositions of the invention are silicone gums having a slight degreeof cross-linking, as are described for example in WO 96/31188. Thesematerials can impart body, volume and stylability to hair, as well asgood wet and dry conditioning.

The viscosity of the emulsified silicone itself (not the emulsion or thefinal hair conditioning composition) is typically at least 10,000 cst.In general we have found that conditioning performance increases withincreased viscosity. Accordingly, the viscosity of the silicone itselfis preferably at least 60,000 cst, most preferably at least 500,000 cst,ideally at least 1,000,000 cst. Preferably the viscosity does not exceed10⁹ cst for ease of formulation.

Emulsified silicones for use in the shampoo compositions of theinvention will typically have an average silicone droplet size in thecomposition of less than 30, preferably less than 20, more preferablyless than 10 μm. We have found that reducing the droplet size generallyimproves conditioning performance. Most preferably the average siliconedroplet size of the emulsified silicone in the composition is less than2 μm, ideally it ranges from 0.01 to 1 μm. Silicone emulsions having anaverage silicone droplet size of ≦0.15 μm are generally termedmicroemulsions.

Suitable silicone emulsions for use in the invention are alsocommercially available in a pre-emulsified form.

Examples of suitable pre-formed emulsions include emulsions DC2-1766,DC2-1784, and microemulsions DC2-1865 and DC2-1870, all available fromDow Corning. These are all emulsions/microemulsions of dimethiconol.Cross-linked silicone gums are also available in a pre-emulsified form,which is advantageous for ease of formulation. A preferred example isthe material available from Dow Corning as DC X2-1787, which is anemulsion of cross-linked dimethiconol gum. A further preferred exampleis the material available from Dow Corning as DC X2-1391, which is amicroemulsion of cross-linked dimethiconol gum.

A further preferred class of silicones for inclusion in shampoos andconditioners of the invention are amino functional silicones. By “aminofunctional silicone” is meant a silicone containing at least oneprimary, secondary or tertiary amine group, or a quaternary ammoniumgroup.

Examples of suitable amino functional silicones include

-   (i) polysiloxanes having the CTFA designation “amodimethicone”, and    the general formula:

HO—[Si(CH₃)₂—O—]_(x)—[Si(OH)(CH₂CH₂CH₂—NH—CH₂CH₂NH₂)—O—]_(y)—H

in which x and y are numbers depending on the molecular weight of thepolymer, generally such that the molecular weight is between about 5,000and 500,000.

-   (ii) polysiloxanes having the general formula:

R′_(a)G_(3-a)-Si(OSiG₂)_(n)-(OSiG_(b)R′_(2-b))_(m)—O—SiG_(3-a)-R′_(a)

in which:G is selected from H, phenyl, OH or C₁₋₈ alkyl, e.g. methyl;a is 0 or an integer from 1 to 3, preferably 0;b is 0 or 1, preferably 1;m and n are numbers such that (m+n) can range from 1 to 2000, preferablyfrom 50 to 150;m is a number from 1 to 2000, preferably from 1 to 10;n is a number from 0 to 1999, preferably from 49 to 149, andR′ is a monovalent radical of formula —C_(q)H_(2q)L in which q is anumber from 2 to 8 and L is an amino functional group selected from thefollowing:

—NR″—CH₂—CH₂—N(R″)₂

—N(R″)₂

—N⁺(R″)₃A⁻

—N⁺H(R″)₂A⁻

—N⁺H₂(R″)A⁻

—N(R″)—CH₂—CH₂—N⁺H₂(R″)A⁻

in which R″ is selected from H, phenyl, benzyl, or a saturatedmonovalent hydrocarbon radical, e.g. C₁₋₂₀ alkyl, and A is a halide ion,e.g. chloride or bromide.

Suitable amino functional silicones corresponding to the above formulainclude those polysiloxanes termed “trimethylsilylamodimethicone” asdepicted below, and which are sufficiently water insoluble so as to beuseful in compositions of the invention:

Si(CH3)3-O—[Si(CH3)2-O-]x-[Si(CH3)(R—NH—CH2CH2NH2)-O-]y-Si(CH3)3

wherein x+y is a number from about 50 to about 500, andwherein R is an alkylene group having from 2 to 5 carbon atoms.Preferably, the number x+y is in the range of from about 100 to about300.

-   (iii) quaternary silicone polymers having the general formula:

{(R¹)(R²)(R³)N⁺CH₂CH(OH)CH₂O(CH₂)₃[Si(R⁴)(R⁵)—O—]_(n)—Si(R⁶)(R⁷)—(CH₂)₃—O—CH₂CH(OH)CH₂N⁺(R⁸)(R⁹)(R¹⁰)}(X⁻)₂

wherein R¹ and R¹⁰ may be the same or different and may be independentlyselected from H, saturated or unsaturated long or short chain alk(en)yl,branched chain alk(en)yl and C₅-C₈ cyclic ring systems;R² thru' R⁹ may be the same or different and may be independentlyselected from H, straight or branched chain lower alk(en)yl, and C₅-C₈cyclic ring systems;n is a number within the range of about 60 to about 120, preferablyabout 80, andX⁻ is preferably acetate, but may instead be for example halide, organiccarboxylate, organic sulphonate or the like. Suitable quaternarysilicone polymers of this class are described in EP-A-0 530 974.

Amino functional silicones suitable for use in shampoos and conditionersof the invention will typically have a mole % amine functionality in therange of from about 0.1 to about 8.0 mole %, preferably from about 0.1to about 5.0 mole %, most preferably from about 0.1 to about 2.0 mole %.In general the amine concentration should not exceed about 8.0 mole %since we have found that too high an amine concentration can bedetrimental to total silicone deposition and therefore conditioningperformance.

The viscosity of the amino functional silicone is not particularlycritical and can suitably range from about 100 to about 500,000 cst.

Specific examples of amino functional silicones suitable for use in theinvention are the aminosilicone oils DC2-8220, DC2-8166, DC2-8466, andDC2-8950-114 (all ex Dow Corning), and GE 1149-75, (ex General ElectricSilicones).

Also suitable are emulsions of amino functional silicone oils with nonionic and/or cationic surfactant.

Suitably such pre-formed emulsions will have an average amino functionalsilicone droplet size in the shampoo composition of less than 30,preferably less than 20, more preferably less than 10 μm. Again, we havefound that reducing the droplet size generally improves conditioningperformance. Most preferably the average amino functional siliconedroplet size in the composition is less than 2 μm ideally it ranges from0.01 to 1 μm.

Pre-formed emulsions of amino functional silicone are also availablefrom suppliers of silicone oils such as Dow Corning and GeneralElectric. Specific examples include DC929 Cationic Emulsion, DC939Cationic Emulsion, and the non-ionic emulsions DC2-7224, DC2-8467,DC2-8177 and DC2-8154 (all ex Dow Corning).

An example of a quaternary silicone polymer useful in the presentinvention is the material K3474, ex Goldschmidt.

Compositions according to the present invention may also comprise adispersed, non-volatile, water-insoluble oily conditioning agent.

This component will be dispersed in the composition in the form ofdroplets, which form a separate, discontinuous phase from the aqueous,continuous phase of the composition. In other words, the oilyconditioning agent will be present in the shampoo composition in theform of an oil-in-water emulsion.

By “insoluble” is meant that the material is not soluble in water(distilled or equivalent) at a concentration of 0.1% (w/w), at 250° C.

Suitably, the D_(3,2) average droplet size of the oily conditioningcomponent is at least 0.4, preferably at least 0.8, and more preferablyat least 1 μm. Additionally, the D_(3,2) average droplet size of theoily conditioning component is preferably no greater than 10, morepreferably no greater 8, more preferably no greater than 5, yet morepreferably no greater than 4, and most preferably no greater than 3.5μm.

The oily conditioning agent may suitably be selected from oily or fattymaterials, and mixtures thereof.

Oily or fatty materials are preferred conditioning agents in the shampoocompositions of the invention for adding shine to the hair and alsoenhancing dry combing and dry hair feel.

Preferred oily and fatty materials will generally have a viscosity ofless than 5 Pa·s, more preferably less than 1 Pa·s, and most preferablyless than 0.5 Pa·s, e.g. 0.1 Pa·s and under as measured at 25° C. with aBrookfield Viscometer (e.g. Brookfield RV) using spindle 3 operating at100 rpm.

Oily and fatty materials with higher viscosities may be used. Forexample, materials with viscosities as high as 65 Pa·s may be used. Theviscosity of such materials (i.e. materials with viscosities of 5 Pa·sand greater) can be measured by means of a glass capillary viscometer asset out further in Dow Corning Corporate Test Method CTM004, Jul. 20,1970.

Suitable oily or fatty materials are selected from hydrocarbon oils,fatty esters and mixtures thereof.

Hydrocarbon oils include cyclic hydrocarbons, straight chain aliphatichydrocarbons (saturated or unsaturated), and branched chain aliphatichydrocarbons (saturated or unsaturated). Straight chain hydrocarbon oilswill preferably contain from about 12 to about 30 carbon atoms. Branchedchain hydrocarbon oils can and typically may contain higher numbers ofcarbon atoms. Also suitable are polymeric hydrocarbons of alkenylmonomers, such as C₂-C₆ alkenyl monomers. These polymers can be straightor branched chain polymers. The straight chain polymers will typicallybe relatively short in length, having a total number of carbon atoms asdescribed above for straight chain hydrocarbons in general. The branchedchain polymers can have substantially higher chain length. The numberaverage molecular weight of such materials can vary widely, but willtypically be up to about 2000, preferably from about 200 to about 1000,more preferably from about 300 to about 600.

Specific examples of suitable hydrocarbon oils include paraffin oil,mineral oil, saturated and unsaturated dodecane, saturated andunsaturated tridecane, saturated and unsaturated tetradecane, saturatedand unsaturated pentadecane, saturated and unsaturated hexadecane, andmixtures thereof. Branched-chain isomers of these compounds, as well asof higher chain length hydrocarbons, can also be used. Exemplarybranched-chain isomers are highly branched saturated or unsaturatedalkanes, such as the permethyl-substituted isomers, e.g., thepermethyl-substituted isomers of hexadecane and eicosane, such as2,2,4,4,6,6,8,8-dimethyl-10-methylundecane and2,2,4,4,6,6-dimethyl-8-methylnonane, sold by Permethyl Corporation. Afurther example of a hydrocarbon polymer is polybutene, such as thecopolymer of isobutylene and butene. A commercially available materialof this type is L-14 polybutene from Amoco Chemical Co. (Chicago, Ill.,U.S.A.).

Particularly preferred hydrocarbon oils are the various grades ofmineral oils. Mineral oils are clear oily liquids obtained frompetroleum oil, from which waxes have been removed, and the more volatilefractions removed by distillation. The fraction distilling between 250°C. to 300° C. is termed mineral oil, and it consists of a mixture ofhydrocarbons ranging from C₁₆H₃₄ to C₂₁H₄₄. Suitable commerciallyavailable materials of this type include Sirius M85 and Sirius M125, allavailable from Silkolene.

Suitable fatty esters are characterised by having at least 10 carbonatoms, and include esters with hydrocarbyl chains derived from fattyacids or alcohols, e.g., monocarboxylic acid esters, polyhydric alcoholesters, and di- and tricarboxylic acid esters. The hydrocarbyl radicalsof the fatty esters thereof can also include or have covalently bondedthereto other compatible functionalities, such as amides and alkoxymoieties, such as ethoxy or ether linkages.

Monocarboxylic acid esters include esters of alcohols and/or acids ofthe formula R′COOR in which R′ and R independently denote alkyl oralkenyl radicals and the sum of carbon atoms in R′ and R is at least 10,preferably at least 20.

Specific examples include, for example, alkyl and alkenyl esters offatty acids having aliphatic chains with from about 10 to about 22carbon atoms, and alkyl and/or alkenyl fatty alcohol carboxylic acidesters having an alkyl and/or alkenyl alcohol-derived aliphatic chainwith about 10 to about 22 carbon atoms, benzoate esters of fattyalcohols having from about 12 to 20 carbon atoms.

The monocarboxylic acid ester need not necessarily contain at least onechain with at least 10 carbon atoms, so long as the total number ofaliphatic chain carbon atoms is at least 10. Examples include isopropylisostearate, hexyl laurate, isohexyl laurate, isohexyl palmitate,isopropyl palmitate, decyl oleate, isodecyl oleate, hexadecyl stearate,decyl stearate, isopropyl isostearate, dihexyldecyl adipate, lauryllactate, myristyl lactate, cetyl lactate, oleyl stearate, oleyl oleate,oleyl myristate, lauryl acetate, cetyl propionate, and oleyl adipate.

Di- and trialkyl and alkenyl esters of carboxylic acids can also beused. These include, for example, esters of C₄-C₈ dicarboxylic acidssuch as C₁-C₂₂ esters (preferably C₁-C₆) of succinic acid, glutaricacid, adipic acid, hexanoic acid, heptanoic acid, and octanoic acid.Examples include diisopropyl adipate, diisohexyl adipate, anddiisopropyl sebacate. Other specific examples include isocetyl stearoylstearate, and tristearyl citrate.

Polyhydric alcohol esters include alkylene glycol esters, for exampleethylene glycol mono and di-fatty acid esters, diethylene glycol mono-and di-fatty acid esters, polyethylene glycol mono- and di-fatty acidesters, propylene glycol mono- and di-fatty acid esters, polypropyleneglycol monooleate, polypropylene glycol monostearate, ethoxylatedpropylene glycol monostearate, polyglycerol poly-fatty acid esters,ethoxylated glyceryl monostearate, 1,3-butylene glycol monostearate,1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester,sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid estersand mono-, di- and triglycerides.

Particularly preferred fatty esters are mono-, di- and triglycerides,more specifically the mono-, di-, and tri-esters of glycerol and longchain carboxylic acids such as C₁-C₂₂ carboxylic acids. A variety ofthese types of materials can be obtained from vegetable and animal fatsand oils, such as coconut oil, castor oil, safflower oil, sunflower oil,cottonseed oil, corn oil, olive oil, cod liver oil, almond oil, avocadooil, palm oil, sesame oil, peanut oil, lanolin and soybean oil.Synthetic oils include triolein and tristearin glyceryl dilaurate.

Specific examples of preferred materials include cocoa butter, palmstearin, sunflower oil, soyabean oil and coconut oil.

The oily or fatty material is suitably present at a level of from 0.05to 10, preferably from 0.2 to 5, more preferably from about 0.5 to 3 wt%.

In hair treatment compositions containing a conditioning agent, it ispreferred that a cationic polymer also be present.

The compositions of the present invention may also contain adjuvantssuitable for hair care. Generally such ingredients are includedindividually at a level of up to 2, preferably up to 1 wt % of the totalcomposition.

Among suitable hair care adjuvants, are:

-   (i) natural hair root nutrients, such as amino acids and sugars.    Examples of suitable amino acids include arginine, cysteine,    glutamine, glutamic acid, isoleucine, leucine, methionine, serine    and valine, and/or precursors and derivatives thereof. The amino    acids may be added singly, in mixtures, or in the form of peptides,    e.g. di- and tripeptides. The amino acids may also be added in the    form of a protein hydrolysate, such as a keratin or collagen    hydrolysate. Suitable sugars are glucose, dextrose and fructose.    These may be added singly or in the form of, e.g. fruit extracts. A    particularly preferred combination of natural hair root nutrients    for inclusion in compositions of the invention is isoleucine and    glucose. A particularly preferred amino acid nutrient is arginine.-   (ii) hair fibre benefit agents. Examples are:    -   ceramides, for moisturising the fibre and maintaining cuticle        integrity. Ceramides are available by extraction from natural        sources, or as synthetic ceramides and pseudoceramides. A        preferred ceramide is Ceramide II, ex Quest. Mixtures of        ceramides may also be suitable, such as Ceramides LS, ex        Laboratoires Serobiologiques.

This post treatment composition may be in any form preferably in theform chosen from emulsions, solutions, suspensions, gels, creams, andpastes.

The compositions of the present invention may be provided as amulticomponent kit for straightening hair comprising at least twoseparate components. A first component of the kit contains comprises atleast one composition for generating hydroxide ions to relax the hair.The second component comprises at least one composition comprising atleast one basic amino acid.

A preferred method of terminating the lanthionization process is byrinsing the hair with water.

The invention will now be illustrated by the following non-limitingExamples.

EXAMPLES

TABLE 1 Wt % Wt % Example Example Trade Name Chemical Name Supplier A 1Laurex CS Cetyl/stearyl Huntsman 4.80 4.80 Alcohol Perfecta PetroleumJelly- Crompton 0.10 0.10 Petrolatum White Superla No 7 White MineralAmoco 0.25 0.25 Oil CrodalanLA Cetyl Acetate and Croda 0.90 0.90 StearylAcetate and Oleyl Acetate and Acetylated Lanolin Alcohol Arquad 16-29Cetrimonium Akzo Nobel 4.30 4.30 Chloride 29% (CTAC) Glycerol GlycerolSigma/ 0.50 0.50 Aldrich Natrosol Hydroxyethyl- Hercules 0.30 0.30250HHR celluslose Glycerol Monomuls Cognis 5.0 monololeate 90-018 Waterand to 100% to 100% minors

A series of switches were treated with the compositions of table 1immediately after the lanthionization process. 2.5 gm 6″ switches ofAfrican hair were immersed in 150 ml of 3.5% aqueous sodium hydroxidefor 30 minutes at ambient conditions. The switches were then rinsedunder tepid tap water for 1 minute. This process was repeated 4 times.After the final treatment the switches were placed in 150 ml ofpost-lanthionization composition for 15 minutes followed by rinsing andoven drying for 45 minutes at 50° C.

Sensory Evaluation

The switches were assessed for the following sensory attributes;dryness, brittle, silkiness and gloss using the paired comparisonBradley-Terry analyses. (3 product testing).

Examples of the invention were directly compared to the comparativeExamples.

Active, Base Non-brittle Std Err Non-dry Std Err Gloss Std Err Silky StdErr Example 1 preference 66.20 (18.07) 69.95 (18.09) 67.95 (19.17) 66.35(18.53) scores

Numbers refer to the percentage of panelists who selected Example 1 asscoring higher on a attribute compared with comparative Example A(control conditioner with no active).

In-Vitro Hair Breakage Test

A set of switches were treated as described above.

The weight of the switches was recorded. The switches were mounted in anautomatic combing device and subjected to a total of 6 hours drycombing. The final weight was recorded.

The percentage breakage was calculated as the final weight/initialweight×100.

Treatment % Of Broken Fibres Std Dev Control 24.5 5.2 relaxed ×4 and nopost treatment Example A Post treatment 5.6 2.2 Example 1 Post treatment2.5 1.5

1. A method for relaxing hair comprising the following steps: i)applying to the hair for a sufficient period of time to lanthionize thehair a relaxer composition; ii) terminating the lanthionization process;iii) applying to the lanthionized hair a post-lanthionizationcomposition comprising a monoglyceride having a C16 to C22 alkyl estergroup.
 2. A method according to claim 1 in which the total level ofmono-glyceride within the post-treatment composition is from 3.5 to 7.5wt %.
 3. A method according to claim 1 in which the monoglyceride isglycerol monooleate.
 4. A method according to claim 1 in which thepost-treatment composition further comprises a cationic conditioningsurfactant.
 5. A method according to claim 4 in which the weight ratioof cationic conditioning agent to monoglyceride within thepost-treatment composition is from 1:5 to 5:1.
 6. A method according toclaim 1 in which the post-treatment composition further comprises asilicone.
 7. A method according to claim 1 in which the relaxercomposition comprises at least one hydroxide ion generator whichgenerates hydroxide ions in situ.
 8. Use of a monoglyceride having a C16to C22 alkyl ester group in a post-treatment composition for decreasinghair breakage.